move dev notes to main readme

README.md

@@ -6,7 +6,7 @@
 
 
 This Python implementation of the Thermodynamic Equation of Seawater 2010 (TEOS-10) is based primarily on numpy ufunc wrappers of the GSW-C implementation.
-This library replaces the original [python-gsw](https://github.com/TEOS-10/python-gsw) pure-python implementation..
+This library replaces the original [python-gsw](https://github.com/TEOS-10/python-gsw) pure-python implementation.
 The primary reasons for this change are that by building on the C implementation we reduce code duplication and we gain an immediate update to the 75-term equation.  
 Additional benefits include a major increase in speed,
 a reduction in memory usage,
@@ -47,17 +47,6 @@ The development version of the package can be installed from a clone of the repo
 pip install .
 ```
 
-It is neither necessary nor recommended to run the code generators,
-and no instructions are provided for them;
-their output is included in the repo.
-You will need a suitable compiler:
-gcc or clang for unix-like systems,
-or the MSVC compiler set used for Python itself on Windows.
-For Windows, some of the source code has been modified to C++ because the MSVC C compiler does not support the
-C99 complex data type used in original GSW-C.
-
-To test, after installation, run "pytest" from the source directory.
-
 ## Citation
 
 If you use GSW-Python, please cite: McDougall, T.J. and P.M. Barker, 2011: Getting started with TEOS-10 and the Gibbs Seawater (GSW) Oceanographic Toolbox, 28pp., SCOR/IAPSO WG127, ISBN 978-0-646-55621-5
@@ -81,4 +70,65 @@ It adds CF compliant attributes when possible, units, and name.
 ## Note on generating the docstrings
 
 The autogenerated docstrings are checked with codespell in the CIs.
-when autogenerating them we need to run ``pre-commit run --all-files`` and fix the documentation issues found.
+When autogenerating them we need to run ``pre-commit run --all-files`` and fix the documentation issues found.
+
+## Development notes
+
+You will need a suitable compiler:
+gcc or clang for unix-like systems,
+or the MSVC compiler set used for Python itself on Windows.
+For Windows, some of the source code has been modified to C++ because the MSVC C compiler does not support the
+C99 complex data type used in original GSW-C.
+
+The subdirectory ('tools') contains modules and scripts for
+maintaining the code that is autogenerated from the upstream
+GSW-Matlab and GSW-C repos.  The scripts are to be run from
+this directory; they make assumptions about where they
+are, and about where upstream repos are.  Specifically, it
+is assumed that GSW-Matlab, GSW-C, and GSW-Python git repos
+are all in the same base directory.
+
+### Scripts
+- `copy_from_GSW-C.py`: copies the relevant .c and .h files from a
+    sibling GSW-C repo, if the latter are newer.
+- `mat2npz.py`: generates an npz file in gsw/tests containing the
+    test data and check values from the gsw_data_v3_0.mat file
+    in the sibling GSW-Matlab repo.
+- `make_ufuncs.py`: Generates the src/_ufuncs.c file to turn the
+    scalar C functions into numpy ufuncs.  It writes ufuncs.list
+    in the current directory as a record of the ufunc names.
+    Functions are identified as ufunc candidates based on their
+    signatures, parsed from src/c_gsw/gswteos-10.h.
+- `make_wrapped_ufuncs.py`: Generates gsw/_wrapped_ufuncs.py based on
+    the output of make_ufuncs.py.  It adds docstrings constructed
+    from the Matlab help text.
+- `fix_wrapped_ufunc_typos.py`: Fixes docstring typos that have been
+    identified, but not yet fixed, in the GSW-Matlab repo.
+- `codegen`: Runs the last three python scripts.
+
+### Modules
+- `c_header_parser.py`: Functions for taking apart the function
+    declarations in gswteos-10.h.
+- `matlab_parser.py`: Functions specifically for reading the GSW-Matlab
+    function signatures and for splitting out the help text.
+- `docstring_parts.py`: Blocks of text for assembling docstrings.
+- `docstring_utils.py`: Functions for assembling docstrings in numpydoc
+    format.
+- `categories.py`: Functions for listing gsw function names by category.
+    This is not used by any of the other functions or scripts, but
+    was used when initially categorizing the functions for inclusion
+    in submodules.
+
+### Notes
+
+- In addition to the generated src/_ufuncs.c, there are two C files
+    that are hand-written: src/method_bodies.c and src/method_def_entries.c.
+    These are imported by src/_ufuncs.c. They handle some C functions
+    that are not suitable for ufuncs.
+- Specialized Matlab parsing is also done in gsw/tests/check_functions.py,
+    which is used by gsw/tests/test_check_functions.py; see the docstring
+    of the former for more info.
+
+### Testing
+
+To test, after installation, run "pytest --pyargs gsw".